<?php
$marks = 56;

if($marks >= 75) {
  echo "HNS";
} else {

  if($marks < 75 && $marks >= 60) {
    echo "FIRST";
  } else {

    if($marks < 60 && $marks >= 50) {
      echo "SECOND";
    } else {

      if($marks < 50 && $marks >= 40) {
        echo "THIRD";
      } else {
        if($marks < 40 ) {
          echo "FAIL";
        }
      }
    }
  }
}
